Method of preparing asbestos for use as an insulation for metallic surfaces.



, UNITED STATES PATENT OFFICE.

JOHN ALLEN HEANY, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE TETER-HEANY DEVELOPING COMPANY, OF PHILADELPHIA, PENN SYLVANIA, AND CHARLESTON, WEST VIRGINIA.

VEST VIRGINIA, A CORPORATION OF METHOD OF PREPARING ASBESTOS FOR USE AS AN INSULATION FOR METALLIC SURFACES.

SPECIFICATION forming part of Letters Patent N 0. 703,200, dated June 24;, 1902.

Original application filed November 9, 1901, Serial No. 81,279. Divided and this application filed January 8, 1902.

Serial No. 88,897. (No specimens.)

f0 ail? ii /@0777, it may concern;

Be it known that 1, JOHN ALLEN HEANY, a citizen of the United States, residing at the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Methods of Preparing Asbestos for Use as an Insulation for Metallic Surfaces, of which the following is a specification.

My invention has relation to the insulation of electric wires or other metallic surfaces by means of a compound containing asbestos and is a division of my application filed Novemher 9, A. D. 1901, under Serial No. 81,279.

Heretofore the use of asbestos as an insulating material has been limited by reason of the fact that it could not be applied to the metal in a thin pliable form, and yet be made waterproof, fireproof, and adhesive under conditions of excessive heat applied through the metallic surface or extraneously applied to the asbestos covering. As is well known, asbestos is an absorbent of moisture and is not absolutely fireproof, because if exposed to a Bunsen fiame the fiber of asbestos loses its flexibility and becomes exceedingly brittle by reason of the driving off of the water of crystallization. WVhen so heated, a chemical change in the asbestos results in its deterioration as an insulating material, the asbestos being converted into oxids and the fiber made brittle.

The principal object of my present invention is to provide a method of preparing asbestos as an insulation or covering for electric wires or metallic surfaces, so that it shall be fireproof, waterproof, and su fficiently thin, pliable, and adhesive to permit the wire or surface to be bent into helices or coils without impairing the efficiency of the asbestos covering.

In carrying out my invention the metallic wire or surface is firstcoated or covered with a paste or cement containing the following ingredients, to wit: first composition-fishglue or gelatinous or albuminous substances combined with lime, either wholly or 'partly slaked; second solution-sulfate of ammonia,

' boracic acid, sulfate of soda, chlorid of ammonia, chlorid of soda, and Water. After either the first composition or the second solution has been applied to the metallic wire or surface the asbestos is first treated with the second solution containing the chemical or metallic salts, as above set forth, is then dried and picked into flaky or fibrous form, and then twisted under pressure upon the coated and sticky wire or metallic surface previously coated with either the first composition or the second solution. The asbestos covering thus applied may then be covered or coated with a paste or cement containing the first composition of lime with the albuminous or gelatinous material mixed with the solution of chemical or metallic salts, as above set forth, and, if desired, is again pressed down upon the wire or metallic sur face. The coating or covering thus applied to the metallic wire or surface will be found to be a perfect insulation, water and fire proof, thin, pliable, and flexible, and adhering to the wire or metallic surface under extraordinary conditions of temperature.

If desired, and in some instances this is preferable, the wire or metallic surface before it is covered with the paste or cement in the first instance may be treated or immersed in a bath of zinc chlorid, which chlorid is allowed to dry upon the wire or surface before the paste or cement containing lime and albuminous or gelatinous substances combined with the second solution of chemical or metallic salts is applied to the wire. The zinc chlorid in this instance serves not only to clean the wire or metal surface; but when thewire or surface is subjected to extreme heat after the insulation has been applied the chlorin is driven off and metallic zine remaining will chemically combine with the -metal and with certain of the ingredients of the paste or cement. The adhesion of the asbestos to the metal Wire or surface is thus increased.

Having thus described the nature and object of my invention, what I claim as new,

and desire to secure by Letters Patent, is- 1. The method of preparing asbestos for use as an insulation for metallic surfaces,

boracic acid, sulfate of soda, ohlorid of am monia and chlorid of soda in water, drying the asbestos and then separating the dried asbestos into flaky or fibrous form, substantially as and for the purposes described.

In testimony whereof I have hereunto set my signature in the presence of two subscrib- 2o ing witnesses.

JOHN ALLEN HEANY.

' Witnesses:

J. WALTER DOUGLASS, V THOMAS M. SMITH. 

